Just so you know, none of the buttons do anything, it's just a sprite. The numbers at the top of the calculator mean nothing. Numbers are asked, not buttons pressed. When it asks you if you have a third/fourth number, answer with "Yes" capitalized correctly for it to ask for your third/fourth number. When you answer the "What do you want to do" question, +=plus -= minus x= times and /=divide. Tell me if there are any bugs or it gave you the wrong number.
Just something I learned to do in my computer science class XD Mr Singer is the best